WIP: ADR 1

Address the Lambda Function Handler name interdependency between this
repo and the infrastructure repo.

docs/adrs/01-pick-lamba-handler-name.md

@@ -0,0 +1,22 @@
+# 1. Pick the Custom Domain Lambda Handler Name
+
+Date: 2024-01-19
+
+## Status
+
+Accepted
+
+## Context
+
+Per the AWS documentation for [Lambda function handlers in Python](https://docs.aws.amazon.com/lambda/latest/dg/python-handler.html?icmpid=docs_lambda_help), we need to ensure that what Terraform defines for the handler when it create the Lambda function matches up with what the developer uses for a file name and function name in the dependent application repository.
+
+See ADR#8 in [mitlib-tf-workloads-libraries-website](https://github.com/MITLibraries/mitlib-tf-workloads-libraries-website) which says the exact same thing.
+
+## Decision
+
+1. The "custom domain" Lambda function handler is `lambda_handler`.
+2. The "custom domain" Lambda function filename in which the handler function lives is `lambda_edge.py`.
+
+## Consequences
+
+If anyone decides to rename Python files in this repo, then the definition of the Lambda function in the [mitlib-tf-workloads-libraries-website](https://github.com/MITLibraries/mitlib-tf-workloads-libraries-website) repo might need to be udpated.